World Cup 2014: football's offside rule explained

Of the round ball game's 17 official rules (yep there are 17) the offside rule is one of the most discussed, confused, and contested; the subject of countless bar arguments and screaming matches at games.

With the help of some paper all-stars, News Online looks at how the rule works, and why it exists.

The second way a player can be 'involved in active play', is by interfering with an opponent.

This means preventing an opponent from playing or being able to play the ball, by obstructing the opponent's line of vision or movements, or making a gesture or movement, which in the opinion of the referee deceives or distracts an opponent.

The first exemption is that a player can't be offside in their own half, so even if they play at the ball and there is only one (or even no defenders) between them and the goal they will not be ruled offside.